Why is it that when girls break up with you or get broken up with. They can't be mature and start being rude?

Like me and my ex of a few years just broke up and im trying to grab my things from the house we shared and now she's being extremely rude. We literally broke up for no reason. She literally attacked me and I walked away and she got mad I didn't hit back. She mad because I left immediately after being hit , that's the reason we broke up smh.
Why is it that when girls break up with you or get broken up with. They can't be mature and start being rude?
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